Refrigerating system



Nov. 21, 1933. E. A. WEAVER 1,935,866

REFRIGERATING SYSTEM Original Filed Feb. 11, 1929 Iradeaoba boiling the solution. For example, I have found that fatty acids such as propionic, butyric, and oleic acids are suitable absorbent liquids, and furthermore do not have an objectionable tendency to corrode the metal of which the apparatus is preferably formed. I have found that refrigerants of suitable volatility may include substituted ammonia bases or allwl amines, such as propylamine, allylamine, diethylamine and triethylamine. Other organic acids such as valerianic, oenanthic, caprylic, caproic, acetic, formic and lactic acids are also more or less suitable absorbents, while cresole and other phenolic liquids also have some suitable characteristics for this purpose.

By selecting suitable pairs of liquids of this character which have boiling points differing from each other sufficiently so that the more volatile fluid may be readily separated from the less volatile fluid, I have found that a con inuously operable absorption system may be run at pressures not substantially greater than, and preferably no higher. than atmospheric pressure. In the accompanying drawing, the figure diagrammatically illustrates one type of refrigerating system to which my invention is applicable.

Referring to the accompanying drawing, it may be understood that energy is imparted to the system by a heating factor 1 which may conveniently be a gas burner provided with an upstanding flue 2 about the lower portion of which a boiler or generator 3 is arranged. This generator contains a solution of. the preferred absorbent and refrigerant liquids, for example, an absorbent comprising a weak fatty acid such as propionic or butyric or oleic acid, and refrigerant comprising propylamine, allylamine, diethylamine or triethylamine. A duct 4 juxtaposed to the flue 2 extends downwardly into the upper part of the generator 3 and preferably has its lower end disposed substantially at the normal surface of the liquid contained in the generator so that in actual operation of the apparatus this liquid level alternately rises above and is depressed below the end of pipe 4, such an action resulting in the upward propulsion of alternate slugs of the liquid solution and bodies of vaporized refrigerant which is passing out of the absorbent-refrigerant solution. Additional refrigerant is vaporized out of the liquid slugs during their passage up duct 4, du to the heat received from flue 2.

The upper end of pipe 4 is joined to the inter-- mediate part of the upwardly extending duct 6 in such a-manner that the liquid coming from the former flows downwardly through a cooler 'I to the absorber 8, while the refrigerant vapor rises to a condenser 9. The latter may be air-cooled or it may be provided with a suitable cooling jacket 10 receiving cooling water or the like through a pipe 11 and discharging the same through an outlet pipe 12. The refrigerant vapor is liquefied in condenser 10, the liquid refrigerant running downwardly from this condenser into the cooler or evaporator 15. This evaporator is provided with a series of staggered plates 16 which cause the refrigerant stream to be broken up and to flow downwardly alonga tortuous path so that it is readily vaporized. This vaporization occurs due to the tendency of the refrigerant vapor to be-drawn to the absorbent liquid in the absorber 8, the latter being connected to the cooler by a pipe 20. Thus a constant flow of refrigerant vapor from the evaporator to the absorber is induced by the tendency of the absorbent to take up the refrigerant vapor. I

check valve or the like.

The absorber may be cooled by any suitable means such'as a series of radiating fins of a, cooling coil 21 wrapped therearound; the latter may receive water from any suitable source of supply and discharge the same to the pipe 11 that directs the water to the jacket about the refrigerant condenser. The combined refrigerant and absorbent fluids may be returned from the absorber 8 to the generator 3 by a drain 25.

In order to permit the refrigerant to be at different partial pressures in different parts of the system an inert gas is contained within the same. Such a gas is preferably non-inflammable and may have a density (as well as a pressure when contained in the system) substantially of the order of that of atmospheric air; for example,

nitrogen may be utilized for this purpose- Helium is also advantageous, especially in view of its lower density. c

The duct 20 connects the evaporator with the absorber so that the refrigerant vapor, which is preferably heavier than the inert gas, tends to collect adjoining the mouth of duct 20 and to pass to the absorber rnix'ed with some of the inert gas. In the absorber a portion of the refrigerant vapor is removed from the lighter inert gas, being taken up by the absorbent liquid flowing downwardly over plates 30. Theinert gas may then pass upwardly to and through duct 29 which connects the upper portion of the absorber-with the evaporator. Due to the provision of this gas .the partial pressure of the refrigerant in the evaporator may be lower than its pressure in the condenser without necessitating the use of a Similarly the total pressure in the absorber is effective inbalancing the boiler pressure. v

It is to be understood that a system of this character may operate at comparatively low pressures, i. e. at pressures preferably of the order of atmospheric pressure and the refrigerant may readily be liquefied in the condenser at a temperature betweenroom temperature and the boiling point of water, i. e. 100 C. Due to the provision of suitable refrigerant and absorbent liquids, therefore, it is possible to provide a continuously operable absorption refrigerating system normally having a low maximum internal pressure so that even under unusual conditions, such as an interruption in the flow of cooling water, the internal pressures will not become excessive. Furthermore, due to the use of non-inflammable inert gases, fire danger is reduced. 1

It is evident that the simple absorption system shown herewith for purposes of illustration may be provided with various refinements and accessorles, such as heat conserving means, thermostatic controls, etc. For example, the ducts 29 and 20, as well as ducts '1 and 25, respectively, may be arranged in the form of suitable heat interchangers.

While I have described my preferred refrigerant and absorbent liquids, particularly as utilized in a system wherein inert gas is provided to balance the different pressures in different parts of the system and to permit the use of valves to be avoided, it is evident that these liquids-may also be, advantageously used in other types of absorption refrigerating systems, either continuous or intermittent, wherein mechanical valves or other pressure balancing means such for example as liquid columns are used. An example of a system of the latter type is disclosed in the copending application of Daniel F. Comstock, Serial No. 361,273, filed May 8, 1929.

I claim:

1. Refrigerating apparatus comprising a source of heat supply, a generator adjoining the same, an absorbent liquid and a liquid refrigerant carried thereby in solution, one of said liquids being alkaline and the other weakly acidic and their boiling points diiferingby at least 40 C., a condenser adapted to receive refrigerant vapor from the generator, a cooler, a duct to supply liquefled refrigerant from the condenser to the cooler, an absorber adapted to receive weak solution of refrigerant in absorbent liquid, a refrigerant vapor duct connecting the cooler to the absorber, and a duct for returning combined refrigerant and absorbent from the absorber to the generator, and means for permitting differences in pressure of the refrigerant vapor in different parts of the system.

2. Refrigerating apparatus comprising a source of heat supply, a generator adjoining the same, an absorbent liquid and a liquid refrigerant carried in solution thereby, said absorbent comprising an organic acid and said refrigerant comprising a comparatively volatile substituted amine, a condenser adapted to ,receive refrigerant vapor from the generator, a cooler, a duct to supply liquefied refrigerant from the condenser to thecooler, an absorber adapted to receive weak solution of refrigerant in absorbent liquid, a refrigerant vapor duct connecting the cooler to the absorber, and a duct for returning combined refrigerant and absorbent from the absorber to the generator, and means for permitting differences in pressure of the refrigerant vapor in different parts of the system.

3. In a system of the absorption type, the method of refrigeration which comprises circulating a volatile, alkaline compound as a refrigerant by distillation from and absorption in an absorbent comprising a less volatile, weakly acidic compound circulated through a generator and absorber.

4. A refrigerating system comprising an absorbent circuit including a generator and absorber and a refrigerant circuit including the generator, a condenser, an evaporator, and the absorber, said system utilizing an acidic absorbent, and a comparatively volatile, alkaline refrigerant with a vapor pressure under two atmospheres at room temperature.

5. A refrigerating system comprising an absorbent circuit including a generator and absorber and a refrigerant circuit including the generator, a condenser, an evaporator, and the absorber, said system utilizing a weakly acidic absorbent and a comparatively volatile refrigerant which is readily soluble in the absorbent at room temperature and which may be vaporized out of the same at a temperature well below the vaporizing point of the absorbent.

6. A refrigerating system comprising an absorbent circuit including a generator and absorber and a refrigerant circuit including the generator, a condenser, an evaporator, and the absorber, characterized in that the working fluids therein are respectively acidic and alkaline and diifer from each other by at least 40 C. in boiling point, the liquid of lower boiling point having a vapor pressure of not over two atmospheres at room temperature.

7. A refrigerating system comprising an absorbent circuit including a generator and absorber and a refrigerant circuit including the generator, a condenser, an evaporator, and the absorber, characterized in that the working fluids therein are respectively an acid and substituted amine which differ by at least 40 C. in boiling point, being readily soluble in each other at room temperature and readily separable at an elevated temperature.

8. In a system of the absorption type, the method of refrigeration which comprises circulating an alkaline refrigerant by distillation from an acidic absorbent, effecting the condensation of the distilled refrigerant at a pressure under three atmospheres, and absorbing the resulting vapor in absorbent from which the refrigerant has been distilled.

9. An absorption refrigerating system comprising a refrigerant circuit including a generator and absorber, a condenser, and an evaporator, said system utilizing as its working fluids, organic liquids of weakly acidic and alkaline character respectively, readily soluble in each other but readily separable by heat.

10. An absorption system comprising a refrigerant circuit including means for absorbing refrigerant vapor in an absorbent liquid and distilling it therefrom, said system utilizing as its working fluids organic liquids of weakly acidic and alkaline character respectively, readily soluble in each other but readily separable by heat.

11. Refrigerating apparatus comprising a source of heat supply, a generator adjoining the same, an absorbent liquid, and a liquid refrigerant carried thereby in solution, the absorbent being weakly acidic, the refrigerant being comparatively volatile and readily soluble in the absorbent at room temperature, the boiling EASTMAN A. WEAVER. 

